I have a V6S AWD coupe and notice that there is a slight lag when setting off between pressing the accelerator and the transmission really 'biting' ...... it moves slowly and then bites after about quarter of a second ....... only very slight ..... is this normal ??


When at speed the lag doesn't appear to be there

 

Yes, particularly with Dynamic mode off and light throttle application, it takes a bit for the transmission to 'catch.' Less obvious in dynamic mode.

 

Yep - it was the first thing I complained about when I picked up the car - dealer asked if I was in "snow" mode. Technicians said they couldn't find anything wrong and that they'd reset the transmission by disconnecting the battery - I told them that that doesn't actually work on the 8 speed ZF :/

Eventually learned to modulate throttle especially coasting around tight left turns (we drive on the wrong side of the road down here) where if you gave it too much gas it'd decide to snap into a gear half way round which was disconcerting in the wet.

There's actually a transmission TSB from 2 weeks ago with "symptom: 611000 Hesitation/Stumble" which shows that they've enabled the transmission clear routines in the diagnostics suite - might be worth investigating with your dealer.

I've since moved up to an SVR and that always seems like the gearbox is engaged correctly at all times.

 

My V8S doesn't have this lag as far as i can tell, unless im switching direction of travel (F --->R ETC). is it only when you first engage D?

 

Mine either.

Dave

 

I notice it when not in dynamic, and trying to start out smoothly/gently. That's probably why you don't notice it. I think the torque converter is slow to start transferring torque at low revs.

 

Mine does, in fact sometimes when I put my foot down it seems that the car revs before the transmission bites - I can give it a quick rev as though it is a manual with the clutch in.

 

YES, sometimes - 2017 SVR here....

 

YES! V6 RWD and mine is sooooper laggy! Takes a bit to get going off the line but is really bad at highway speeds. If I'm not in manual mode, it takes ~seconds~ to get going. I don't know if it takes that long to shift down from eighth to fifth or what, I don't think it should but it sure does.

 

I find that it lags sometimes and not others.
I always drive in Dynamic mode, and it seems to me the transmission response and kick down depends very much on how you have been driving in the last few minutes.
If you have been driving "enthusiastically" with a fair bit of WOT then it kicks down and gets going fairly quickly, with maybe .5 seconds of lag at most.
But if you have been gently cruising and/or tootling about the 'burbs and/or stuck in peak hour traffic, with no chance to give it WOT, then when you do give it WOT it can seem like ages before it kicks down and decides to take off properly. When I say "ages" it's more like about 2 seconds, but of course when you are wanting instant max throttle response 2 seconds seems like ages. I used to drive naturally aspirated manual trans cars with old fashioned manual throttle cables where I adjusted the cable tension such that the throttle response was instant as soon as I tickled the go pedal, and every one of them simply took off instantly with zero lag as soon as I down-changed and mashed the gas pedal. I miss that level of instant response.
The F-Type lag has been almost the same with the stock tune, the VAP "without larger crank pulley" tune and with the larger crank pulley plus tune, the only difference being that with the pulley and tune the car seems to "wake up" a bit earlier.

 

Yep mine does the exact same thing. Take off slowly and it takes a second or two for the transmission to bite it seems. If anybody finds a solution let us know please.

 

I've assumed that it's due to the torque converter, but the 8HP70 transmission includes a 'Transmission Idle Control', which I suspect is the culprit. It's described on the last page of this:
https://www.dropbox.com/s/b7666doqb4...trans.pdf?dl=0

 

Great description Oz, thanks! Sounds just like mine...

 

Aha! The culprit is identified. Mine does that --teeny lag-- as well. Dealer techs couldn't find or communicate about it. It is so minor that I'll wait for next service to advise them of this tech bulletin. Thanks!

 

Hmmm, there's no tech bulletin I'm aware of. The document I posted explains how the transmission works.

 

 

When I haven't had my early morning coffee, I suffer severe transmission lag. Usually happens when I fall asleep at a long traffic light.

 

I was referring to the TSB, that jallitt mentions.

 

Sorry, missed that...